Learning physics is determined by expected achievements and teaching strategies. Their correlation to student’s conceptual understanding of mechanics, which is the basis of further learning and progress in physics, is especially important. During the regular classes of physics in high schools, the correlation between the characteristics of expected achievements and teaching strategies and student’s conceptual understanding of mechanics was researched. The research included 1093 students within 22 different didactical versions which represent subsamples determined by didactical components syllabus–teacher. The characteristics of expected achievements and teaching strategies are determined by student’s evaluation scales whereas the progress in conceptual understanding of mechanics is measured by the increase of student’s learning outcomes of g (gain) in FCI exams. The characteristics–variables of expected achievements which are significantly positively correlated to g-factor on the level of didactic versions are the student’s familiarity with expected achievements in the model of a simple linear regression (R=0,761, R2=0,579, p<0,01) and the expectations of student’s understanding of physical ideas and models and solving physical problems in life without calculating in the model of multiple linear regression (R=0,745, R2=0,555, p<0,01). The characteristics–variables of teaching strategies which are significantly positively correlated to g-factor on the level of didactic versions are the presence of the methods of conversation and discussion with the students and the methods of investigation physical phenomena through experiments and measurement in the model of multiple linear regression (R=0,710, R2=0,504, p<0,01) as well as the presence of assessment through asking questions during experiments and the measurement in the model of simple linear regression (R=0,488, R2=0,238, p<0,05). The research unambiguously shows that the improvement of a student’s familiarity with expected achievements which lead to the understanding of physical ideas and models as well as solving physical problems in life without calculating, and with the increase in using the methods of conversation and discussion as well as the methods of investigation physical phenomena through experiments and measurement with the integrated assessment, supports the conceptual change and improves the understanding of mechanics.